With the increasing popularity of multimedia content, the need to access such content has increased rapidly, using any type of device and any type of access network. Different types of network access technologies have a wide range of network availability. For example, while network bandwidth available in a GPRS network ranges from 9.6 kbs to 144 kbps, the bandwidth available for 1×EV-DO is in the range of 1 Mbps. Additionally, the network condition changes dynamically for some of the network access technologies, such as wireless networks including WLAN, WiMaX, GPRS, EDGE, and the like. Thus, the available bandwidth for a given network access technology can vary over the duration of a communication session with a receiving device. Similarly, different receiving devices have different resource availability characteristics that can impact the delivery of digital content to all devices. Based on the above demands, there is a critical need to optimize the delivery of multimedia content in order to provide acceptable quality of service and efficient delivery to all devices and over all network access technologies given the available network bandwidth.
Wireless network connections can be especially challenging for delivery of multimedia content. Current real-time video delivery services on the Internet (e.g., Real Networks, Windows Media) have made some attempts at reducing the bandwidth required for delivering video and multimedia content, and adjusting the delivery of content according to the available bandwidth of wireless networks. These approaches, however, do not consider some properties of wireless networks, such as noise over wireless channels, that can significantly impact the received video quality. That is, although such approaches may reduce the delivery bandwidth required, they do not account for quality of the received transmission and cannot generally accommodate the typically noisy and unreliable wireless data network connections encountered by many devices.
Some currently employed techniques to address fluctuations in available bandwidth involve preparing multiple versions of the same content, targeting different network conditions, and switching between the versions based on current network bandwidth availability. Such techniques generally require generating and storing all possible versions for each frame of the multimedia content. Therefore, such techniques require greater processing and storage resources, and are not scalable to address the wide fluctuations of network bandwidth that can be observed in different network access technologies, such as 1×EV-DO.
Other proposed techniques provide customization to the bandwidth and error conditions of wireless channels, which can improve the quality of the rcccived content. Such techniques, however, generally have two primary weaknesses. First, they require compression of the video at the time of transport, which generally leads to a high implementation cost. Second, these methods typically require a specialized video player to be installed on the client, at the receiving device.
Other currently available techniques select the multimedia content clip as a whole, so that all aspects of delivering multimedia content are fixed over the duration of an entire communication session or content clip. Such holistic static techniques cannot account for variations in available bandwidth during the time the content is received. Thus, such techniques cannot provide multimedia streams at the finer granularity needed to accommodate the multitude of available network access technologies and their associated variations.